Amazon.com: Kicker 44CWCD104 Dual 4-Ohm Car Subwoofer Sub Bundle with dB11 RMS Car Amp and Remote, Single Box Kit: Wire,Screws,Spades, RSV10 Single Vented Subwoofer Box and RWK81 Amp Wire Kit with RCA (
Amazon.com: Rockville VS12K54 12" K5 1400w Car Subwoofer in Vented Sub Enclosure Box - 4 Ohm : Everything Else
Twidec /52Pcs Potentiometer 100,200,500,1K,2K,5K,10K,20K,50K,100K,200K,500K,1M ohm Each 4Pcs Single Turn Trimmer Potentiometer Assortment Kit with Storage Box(13 Kinds) 3362P-13: Amazon.com: Industrial & Scientific